Feb 20, 2022
The PJSC Kyiv Cardboard and Paper Mill in Obukhov, Ukraine, recently installed a Valmet IQ quality control system to the corrugator. The target was to improve the quality of the corrugated board to increase package plant productivity and profitability. “The hopes were justified, the system fully meets our requirements,” says Sergey Metelev, chief technologist.
The Obukhov corrugated packaging plant, complete with state-of-the-art equipment from leading European firms, produces more than 300 million square meters of corrugated packaging board per year. The Valmet IQ Installation included moisture and temperature measurements and closed-loop process control from wet-end to dry-end, sheet-based warp measurements, and moisturizers to correct cross-directional profile issues and moisture imbalance.
One of the targets of Valmet IQ installation was to reduce warp, the deformation in the flatness of the corrugated sheet which is one of the most severe quality destroying problems experienced in corrugated board manufacturing.
“Warp is always the biggest problem in corrugated board industry and we are no exception,” says Mr. Sergey Meteliov. “The good result is obvious. We have reduced rejects at the corrugator and seen a decrease in lost time for the elimination of defects in converting. With an increase in average speed also experienced a 6 to 7% growth in productivity of the flat cutting machines. Now the company has the lowest level of waste in its entire history.” After just half-year of system use, the productivity increased by approximately 500,000 m2.
“The operator now has one more control tool - a profiler with the ability to apply water mist along the web profile with automatic control. There is no need to add glue for control of warp. The use of heating has become gentler and more, made it possible to control the moisture content of the workpiece to avoid cracking,” declares Meteliov. “It is not difficult for our operators to manage a simple type of warp. But if we faced the problem of uneven moisture across the width of the machine with a difference of more than 1,5 %, then this created problems with the post-warping after the corrugator. We [now] see the actual moisture and temperature in liners during production and in the corrugated board at the end. These values allow the operator to make the right decisions when process setting. We also implemented the function of wrap-arm control with warp feedback, and this allowed us to maintain the required level of warp at a setpoint value.”
“The total equipment downtime was no more than 36 hours. The system was further configured on a working machine. This is very important for our company,” says Meteliov. Measurements installed on the machine included moisture sensors between the preheaters and glue caps, scanner mounted infrared moisture sensors for the top and bottom liners after the double facer and two Valmet IQ Warp Measurement cameras measuring the sheet profile and warping at the stacker. Two Valmet IQ Moisturizer spraybooms correct moisture variations of external board liners.
“We highly appreciated the work of the Valmet engineer who spent a lot of time with us. The work went smoothly and well-organized. I think that cooperation with our company was equally beneficial for our two companies, a number of ideas were implemented according to our requirements and we think this will become the standard of solutions in future projects of Valmet,” says Meteliov.
“In general, the system is well organized and allows the operator to customize the system to their style,” says Meteliov. Although the system is normally working in auto-mode as a complete management package, in special cases part of it can be selected to be in manual mode. “A button is also implemented to disable the automatic control of the process in one second to transfer full control over of corrugator operation to the operator. This is psychologically important for operators to feel that they can, if necessary, take control of the equipment at any time,” concludes Meteliov.
Valmet has, since 2014, worked with corrugated board manufacturers to cure warp using the Valmet IQ Moisturizer, used extensively in paper production to control curl, wrinkles and heavy edges. Further development resulted in the introduction of the Valmet IQ quality control system specifically designed for corrugators in 2018 and based on decades long experience of measuring and controlling fiber-based webs. The system combines precise online moisture, temperature and warp measurements with reliable closed-loop controls and moisturizers including a reporting system. Users have reported good results with warping significantly decreased after the corrugator, faster on-spec quality after changes and sheets running better in converting with higher speeds. Target-based control according to online measurements instead of recipe-based running, together with model predictive control intelligence, differentiates Valmet’s offering from other suppliers.
Kyiv Cardboard and Paper Mill Private Joint-stock Company is part of the Austrian company Pulp Mill Holding and one of the largest European producers of paper-based products. In terms of total output, the facility produces 30% of all paper products in Ukraine. Recycled paper is the main raw material used in production with the capacity to process more than 1,500 tons of recycled material daily. The box and packing cardboard produced at the facility is utilized in the fabrication of packing for various consumer products.